Realizing the task at hand was not as straightforward as polishing off a previous success, it was back to the drawing board to concept a new design. Our goal was to maintain the same adaptive curve at the prosthetic’s point of contact with the ground so Derby could pivot and play as before, while also attempting a knee-like structure to provide the appropriate amount of give for the new height. Our structural reassessment likewise called for a review of our material choice, leading us to select nylon for the right blend of stability and flex. …When we strapped Derby into this new version, we knew we had a winner. Now up to his natural height, Derby took off at a trot, testing out his new legs with his fluffy tail wagging and pink tongue lolling.